seems like frost damage... often palms get burned but the damage starts being visible weeks later when weather warms up. cold hardy potted palms are notorious for getting winter damage because even with low temperatures the pot freezes and the plant is unable to provide enough water to the leaves when they receive direct sunlight. washingtonias and cycas revoluta are notorious for getting these burns. i always covered my potted palms or moved them to a shadier spot in winter if there are extreme temperature swings or alot of sunlight exposure with a frozen root ball.

check these pictures

Note the tips of those washingtonia that look dried are similar to your trachycarpus palms. just make sure the spear ( where the new folded leafs come out of the stem) is intact and robust.

trachycarpus can get 50 % leaf burn and easily survive.. i've had trachycarpus of a few years old that completely lost all their leaves and survived as long the spear is intact and as long the spear doesn't have any fungal infection they are fine. yours have around 10 % maybe 20 % burn that is nothing to worry about. cut away all dried and damaged foliage but don't cut into the green foliage.

if they weren't in pot but in full ground they probably wouldn't have this damage. also remember that these palms are very cold hardy..

Thank you. That is really helpful. I'll do as you advise.